Seven Best Poka-Yoke Devices

Generally the most effective way to achieve quality is to avoid having defects in the first place. It is much less costly to prevent a problem from ever happening than it is to find and correct the problem after it has occurred. Focusing on prevention activities whose purpose is to reduce the number of defects is better. The idea is to have processes and procedures in place that reduce or eliminate mistakes.

Mistake Proofing is about adding controls to prevent defects, reduce their severity, and detect them if they can occur. The concept was first put to widespread use by Shigeo Shingo within the Toyota Production System (TPS).

The main aim of mistake proofing is:

PREVENT a defect from occurring and when this is not possible, DETECT the defect every time one occurs.

Defects found in later operations or steps of a process have more costs associated with them. There are more materials, labor, overhead, previously reworked product that are at risk. Ultimately if the product gets to the customer as a defect, the intangibles, such as reputation, can exceed the tangible cost.

Poka-yoke devices could be characterized by effectiveness:

GOOD: Detect defect before proceeding to next step.

BETTER: Detects defects while in process at an operation.

BEST: Prevent defects from occurring at all.

The 7 best poka-yoke devices are:

1. Guide Pins

Guide pins of different sizes and/or shapes and placed in the proper locations ensure that parts are being assembled correctly by providing the operator feedback when a mistake has been made. Guide pins can also be used to ensure proper positioning of the part.

Applications

• Proper alignment of a work piece
• Proper orientation of a work piece

Features

• Easy to develop & implement
• May be the result of DFA and DFM activities

Human Error Prevention

• Wrong order, incorrect selection, incorrect positioning, incorrect orientation

2. Error Detection & Alarms

In general, an error detection device can provide a visual alarm such as a flashing light or an audible alarm such as a horn or siren.

These devices signal that a problem is either about to occur or has just happened. With a warning effect, the response is not automatic; someone has to take action.

Application

• The signal must be triggered by something in the process, usually a sensor.

Features

• For audible warnings, there are sirens, horns, bells, and even voice synthesizers.
• For visual alarms, there are lights that flash, rotate, strobe, or just light up.

Warning: If you do use these warnings, the audible or visual signal must stand out from background noise and lights. If audible alarms are used, be careful not to exceed noise standards.

Be careful of “alarm silence buttons.” It is easy to silence the alarm and then forget to take action. Operators need thorough training on how to react to warnings.

3. Limit Switches

Limit switches are electro-mechanical devices that are activated or deactivated when an object comes in contact with them. They are used to detect the presence or absence of an object.

Applications

• Proper positioning of safety devices
• Detection presence or absence of an object
• Positioning of a work piece

Features

• Requires physical contact

Human Error Prevention

• Omission, excessive/insufficient repetition, incorrect selection, incorrect counting, incorrect positioning, incorrect orientation

4. Sensors

A. Proximity Sensors

Proximity sensors emit a high-frequency magnetic field and detect an upset in the field when an object enters it. They can be used to detect the presence or absence of an object.

Applications

• Sensing of tank or bin level
• Confirmation of part or object passes by
• Detection presence or absence of object
• Positioning of work piece

Features

• Non-contact
• Work in harsh environments
• Small sensors are available for installation in tight areas
• Fast response speed

Human Error Prevention

• Omission, excessive/insufficient repetition, incorrect selection, incorrect counting, incorrect positioning, incorrect orientation

B. Laser Displacement Sensors

Laser displacement sensors focus a semiconductor laser beam on a target and use the reflectance of the beam off the target to determine the presence of a target and distance to it.

Applications

• Measuring distance
• Detection of presence or absence of a feature
• Confirmation of part or object passes by
• Positioning of work piece

Features

• Non-contact
• Works in harsh environments
• Some devices can achieve measurement precision down to 0.004 mils (0.1 um)

Human Error Prevention

• Omission, incorrect selection, incorrect counting, failing to sense danger.

5. Vision Systems

Vision systems use cameras to look at a surface and then compare the surface viewed to a “standard” or reference surface stored in the computer. They can be used to detect the presence or absence of an object, the presence of defects, or to make distance measurements.

Applications

• Missing of incorrect parts in an automated assembly line
• Poor quality surfaces or components
• Correct orientation of parts or labels
• Ensure correct relative position
• Color detection

Features

• Non-contact
• Need to have sufficient light
• Flexible (can be reprogrammed for a variety of applications)
• Compact systems are now available

Human Error Prevention

• Omission, incorrect selection, incorrect positioning, incorrect orientation, misrecognition

6. Counters & Timers

Counters (optical or electro-mechanical) look at the occurrence of events. They are usually triggered by some type of sensor. Counters can be programmed to shut down the process if a set number of events do not occur or if too many events occur. Timers can shut down the process if processing time or activity time does not meet or exceeds a preset level.

Applications

• Ensuring the proper number of events occurred
• Preventing failure of equipment or a component usage

Features

• Flexible
• Easy to use
• Easy for people to understand

Human Error Prevention

• Excessive/insufficient repetition, incorrect counting, incorrect positioning, incorrect orientation

7. Checklists

A checklist is a type of informational job aid used to reduce failure by compensating or potential limits of human memory and attention. It helps to ensure consistency and completeness in carrying out a task.

Applications

• Shift Start-up
• Product Changeover
• Equipment Set-up

Features

• Easy to develop
• Easy to use
• Easy for people to understand

Human Error Prevention

• Omission, early/late execution, wrong order, misrecognition

Ideally, poka-yoke ensures that proper conditions exist before actually executing a process step, preventing defects from occurring in the first place. Where this is not possible, poka-yoke performs a detective function, eliminating defects in the process as early as possible. Don't allow defects to occur in your processes by neglecting to prevent mistakes in your work. Use poka-yoke to make the work easier and mistake proof your process.

Post Courtesy of QualityTrainingPortal.com

Lean Quote: Great Things are Done by a Series of Small Things Brought Together

On Fridays I will post a Lean related Quote. Throughout our lifetimes many people touch our lives and leave us with words of wisdom. These can both be a source of new learning and also a point to pause and reflect upon lessons we have learned. Within Lean active learning is an important aspect on this journey because without learning we can not improve.

"Great things are done by a series of small things brought together." — Vincent Van Gogh

In the spirit of doing better, the smallest ideas are likely to be the easiest to adopt and implement. These improvements are sometimes called Point or Mini Kaizen. Making one small change is both rewarding to the person making the change and if communicated to others can lead to a widespread adoption of the improvement and the possibility that someone will improve on what has already been improved. There's no telling what might occur if this were the everyday habit of all team members. 

One of the most counter intuitive facts about small ideas is that they can actually provide a business with more sustainable competitive advantages than big ideas. The bigger the ideas, the more likely competitors will copy or counter them. If new ideas affect the company's products or services, they're directly visible and often widely advertised. And even if they involve behind-the-scenes improvements--say, to a major system or process--they're often copied just as quickly. That's because big, internal initiatives typically require outside sources, such as suppliers, contractors, and consultants, who sell their products and services to other companies, too. Small ideas, on the other hand, are much less likely to migrate to competitors--and even if they do, they're often too specific to be useful. Because most small ideas remain proprietary, large numbers of them can accumulate into a big, competitive advantage that is sustainable. That edge often means the difference between success and failure. 

In a Lean enterprise a strategy of making small, incremental improvements every day, rather than trying to find a monumental improvement once or twice a year equates to a colossal competitive advantage over time and competitors cannot copy these compounded small improvements. 

 

Lean Do’s and Don’ts

Implementing Lean, or any change initiative is difficult.  If it wasn’t, everyone would be doing it, and they’re not. Lean is not easy. It's not easy to understand. It's not easy to implement. And it's especially not easy to sustain. But anyone who has embarked on a so-called lean journey already knows this. Lean, in fact, is hard work and it's a challenge to keep it going.

The following list of do's and don'ts is aimed at focusing on the right things.

Do have an implementation strategy. Companies must determine ahead of time what the vision and direction will be. A proper strategy must assign clear responsibilities and show what resources are to be committed. Metrics and timelines must be defined. Management must decide what core elements are to be deployed and the order of deployment. They also must determine where to start and how Lean will expand throughout the operation. Finally, the strategy should anticipate problem and recovery scenarios. This is critical. Companies can fail by attempting too much. They also can fail by attempting too little and assigning the initiative to a "backburner" status.

Do find a Lean coach. A Lean coach brings a range of experiences from previous Implementations that can help you to ensure that your implementation will be smooth and efficient. A good Lean coach should be continuously pushing your company.

Do develop a value stream map to differentiate the value added steps of a process from the non-value added steps, sum the time for each individual step and determine how much time is given to a process.

Do engage employees in transformation. Employee participation in project decision making is a main principle affecting innovation, productivity, and work satisfaction. Workers typically have more complete knowledge of their work than does management; hence, if workers participate in decision making, decisions will be made with better pools of information.

Don’t focus on tool implementation. Tools do not solve problem but rather people do. It is not about the tools it’s how they are applied. A large number of organizations have failed to produce the desired results from the direct and prescriptive application of Lean tools. The tools themselves have been proven to work in many situations. The difference must then be in how the tools were applied, their appropriateness, but not the tools themselves.

Don't optimize a bad process. Ensure current and future processes are accounted for when implementing lean initiatives.

Don't just set it and forget it. It is important to continually reevaluate your lean manufacturing efforts. Even when you take the long-term into consideration, changes in your business plan, demand levels and industry trends can create possibilities to further improve your factory.

Don’t blindly copy others. Some enterprises think they will get desirable effects by applying Lean tools that others have gotten great achievements. Successful implementation of any Lean tool must be closely related to the management philosophy. So we can’t succeed by imitating and copying practices of others indiscriminately, it must be combined with local culture.

Lean is not a quick fix and you cannot pick and choose the tools you use.   The key to ongoing success is to embed Lean as a philosophy, and a requirement in everybody’s role; ensuring the right levels of line-management responsibility and accountability for gradually implementing the various tools and techniques that support it.

Learning is the key to success—some would even say survival—in today’s organizations. Knowledge should be continuously enriched through both internal and external learning. Learning needs to become part of your daily routine. You are most likely to succeed if you consistently pursue a learning activity each day. Keep learning.

What Do’s and Don’ts would you share with others starting their Lean Journey?

Recognition: Top 10 Management Improvement Blogs

John Hunter with Curious Cat Management Improvement Blog recently ranked the top management improvement blogs. A Lean Journey was ranked 10 out of 43 blogs.

John created a ranking of top management improvement blogs for fun. There is no way to objectively rate blogs by how worthy or valuable they are. He just wanted to create a listing that ranked blogs I thought were worth reading using a collection of metrics that he thinks have some merit.

Here are the top 10 as of now (it will change over time):

The most important factor is my selection of what blogs to include in the first place. Then I rank them using several other factors: link popularity (how many links to the sites, with more authoritative links carrying more weight), a subjective ranking by me, traffic (using an admittedly pretty flawed measure of traffic – but again this is just for fun so…), Twitter authority of the author, domain authority (based on links, not just to the blog, but the web site overall).

I am very honored that John selected my blog and that I made the top 10 list.  It is always wonderful to be recognized for all the effort I put into this labor of love, blogging in the Lean community.

Lean Quote: Leadership is Unlocking People’s Potential to Become Better

On Fridays I will post a Lean related Quote. Throughout our lifetimes many people touch our lives and leave us with words of wisdom. These can both be a source of new learning and also a point to pause and reflect upon lessons we have learned. Within Lean active learning is an important aspect on this journey because without learning we can not improve.

"Leadership is unlocking people’s potential to become better." — Bill Bradley

Successful leaders understand the difference between things and people in an organization. They know that it’s important to manage things, but that it’s even more important to lead people. Leaders don’t just mouth empty phrases like “people are our greatest resource;” they demonstrate by their actions that people – not strategy, products, plans, processes, or systems – are the most critical factor in an organization’s performance. That’s why leaders invest heavily in growing and developing people, while managers see people as objects to be commanded and controlled.

Developing people means challenging people. But just issuing challenges isn’t enough. It would be disrespectful to not also teach a systematic, common means of developing solutions and meeting those challenges. Leaders facilitate the solution of problems by pinpointing responsibility and developing employees. Leaders do not solve other people’s problems.

Your role as a leader is to develop talent to the highest levels of independent and autonomous thinking and execution. Great leaders don’t subscribe to a “Do-It-For-You” methodology of talent management, rather they lead, mentor, coach and develop team members by getting them to buy-into a “Do-It-Yourself” work ethic. Great leaders view each interaction, question or even conflict as a coaching opportunity. Don’t answer questions or solve problems just because you can, rather teach your employees how to do it for themselves. If you make it a habit of solving problems for people, you simply teach them to come to you for solutions at the first sign of a challenge.

The best way to develop employees is not to manage them. You need to coach them to success. This is a process of developing their skills and providing them specific feedback to meet high standards. Employees want to be on the same team with their bosses.

To get people across an organization to systematically work on improvement every day requires teaching the skills behind the solution. And for that to happen, their leaders and mangers also need to practice and learn those skills. Be their coach and lead the team to success!

In order to fully realize potential, you’ll have to add knowledge, skills, and experience. Don’t expect your people to do their best if you don’t equip them with the training they need to perform. And don’t expect your potential to spring forth in a final draft; it takes time to hone your skills and build your confidence. This could come from formal schooling, from the school of hard knocks, or from both. Either way, your education is the house your realized potential will live in.

 

Lean Tips Edition #98 (Tip# 1471-1485)

For my Facebook fans you already know about this great feature. But for those of you that are not connected to A Lean Journey on Facebook or Twitter I post daily a feature I call Lean Tips.  It is meant to be advice, things I learned from experience, and some knowledge tidbits about Lean to help you along your journey.  Another great reason to like A Lean Journey on Facebook.

Click this link for A Lean Journey's Facebook Page Notes Feed.

Here is the next addition of tips from the Facebook page:

Lean Tip #1471 - Focus on the Rate of Production, or Takt Time.

This is a heartbeat measurement for the team. One-piece flow is ideal, but any flow is better than no flow. Pull at the demand of the customer, if possible. Then, pull the material through the process rather than push it along. This may take time. Setting up small work-in-process (WIP) or finished goods inventory (FGI) locations from which teams can pull material through production can be a good place to start. Holding areas also are known as Kanban areas, or supermarkets.

Lean Tip #1472 - Create a Model Line.

Develop a showplace within your shop where everyone can see how it should be done. Start small, but don't pick a project that has no challenges. Develop key measurements before and after the production line so that people can watch the progress of your get-lean initiative. Finally, create a future-state map that acts as your ideal value stream.

Lean Tip #1473 - Don't Wait Until All the Stars Align Before You Begin.

There is never an ideal time to start redoing your manufacturing process. There always are reasons you should wait or gather more data, but a ready-fire-aim approach is not all bad if it is applied to smaller aspects of the project.

Lean Tip #1474 - Develop the Ability to Make “Every Part Every Day”

Develop the ability to make “every part every day” (than every shift, than every hour or pallet or pitch) in fabrication processes upstream of the pacemaker process. By shortening changeover times and running smaller batches in you upstream fabrication processes, those processes will be able to respond to changing downstream needs more quickly.  In turn they will require even less inventory to be held in their supermarkets. This applies to both discrete-parts manufacturing and process industries.

An initial goal at many plants is to make at least “every part every day” for high-running part numbers.

Lean Tip #1475 - Use Kaizens to Teach and Make Rapid Changes

Use a talented and experienced facilitator who has a deep understanding of Lean tools and philosophy but keep training focused on a specific problem. This helps to keep the training relevant to real world situations and ensures that there are tangible outcomes from training activity. The kaizen might have an objective to reduce setup time, reduce waiting time, or increase workplace organization, for instance.

Lean Tip #1476 - Benchmark with other companies

Visit other companies that have successfully implemented lean to get ideas and understanding; other companies are often delighted to present their lean implementation progress. Networking is key to ensure global understanding with other companies implementing Lean.

Lean Tip #1477 - Set up a Lean Enterprise Steering Team

This team would be responsible to provide support in the planning, resourcing, implementation, and follow-up accountability for implementation. The steering team is often identical to the normal line management team. The internal resources and external consultants would provide consulting support to the team. This infrastructure would resolve inter-departmental issues.

Lean Tip #1478 - Leaders Must Thoroughly Understand, Believe In, and Live Lean

All leaders must understand the work in detail and know how to involve people. If the top is not driving the transformation, it will not happen. Then, to keep the results sustainable you must have a system for both result- based and process based performance measurement including measures for velocity of the overall business process and the individual business processes.

Lean Tip #1479 - Create a Positive Atmosphere

Be tolerant towards mistakes committed in lean environment with a supportive and learning attitude. Have patience with progress as this will be key to get results and also try to create a blame free supportive environment. Have courage to take risks at crucial stages to push things and resources to meet the plan and achieve results.

Lean Tip #1480 - Make Lean Mandatory

If a company looks at Lean transformation as a "nice to do" in spare time or as a voluntary activity, it will simply not happen. It needs to be mandatory and people need to be given the space to think about improvements they can make.

Lean Tip #1481 - Involve Employees in the Change Process.

Employees are not so much against change as they are against being changed. Any time managers are going to implement organizational change, there is always a lag between the time the change has been discussed at the management level and the time the change is going to be implemented. Managers like to play like an ostrich and believe that they are the only ones who know about the changes that are going to take place. Unfortunately, while their heads are stuck in the sand believing that no one else knows, employees are effectively undermining the future changes with negative informal communication…the company grapevine. The sooner you involve employees in the process, the better off you will be implementing the change. A formal communication channel is more effective at implementing change than a negative informal one.

Lean Tip #1482 - Ask Employees For Commitment to Change.

Once change has been announced, it is important that you personally ask for each employee’s commitment to successfully implement the change. It is also important that you assure the employee that if there are problems, you want to hear about them. If a negative employee does not tell you, they will tell other employees why the change will not work.

Lean Tip #1483 - Expand and Improve Communication to Employees.

The change process usually means that normal communication channels need to be improved. First, give employees an opportunity to give you input. Start by becoming more available and asking more questions. Get employees’ opinions and reactions to the changes. Maintain your visibility and make it clear that you are an accessible boss. More importantly, be a careful listener. Second, keep employees updated on a regular basis. Just letting your employees know that you have no new information is meaningful information to them. Strive to be specific; clear up rumors and misinformation that clutter the communication channels. Remember, it is almost impossible to over communicate.

Lean Tip #1484 – Management Should Keep a Positive Attitude.

Your attitude as a manager or supervisor will be a major factor in determining what type of climate is exhibited by your employees. Your attitude is the one thing that keeps you in control. Change can be stressful and confusing. Try to remain upbeat, positive, and enthusiastic. Foster motivation in others. During times of transition and change, try to compensate your employees for their extra effort. Write a brief note of encouragement on their paychecks; leave an affirming message on their voice mail; take them aside and tell them what a great job they are doing; listen to their comments and suggestions. Last, try to instill organizational change as a personal challenge that everyone can meet…with success!

Lean Tip #1485 - Raise Levels of Expectations.

Now more than ever, you should ask more from your employees. It is expected that more work needs to be done during the change process. While it may be most practical to expect less in terms of performance, raise your levels of expectations and theirs. During change, employees are more likely to alter their work habits, so reach for the opportunity and push them to try harder and work smarter. Require performance improvements and make the process challenging, but remember to keep goals realistic in order to eliminate frustration and failure.

Lean Quote: Leader's Actions Inspire Others

On Fridays I will post a Lean related Quote. Throughout our lifetimes many people touch our lives and leave us with words of wisdom. These can both be a source of new learning and also a point to pause and reflect upon lessons we have learned. Within Lean active learning is an important aspect on this journey because without learning we can not improve.

"If your actions inspire others to dream more, learn more, do more and become more, you are a leader." — John Quincy Adams

People do what they have to do for a manager, they do their best for an inspirational leader.  The ability to inspire people to reach great heights of performance and success is a skill that leaders need. Passion, purpose, listening and meaning help make a leader inspirational. Leaders must create a corporate culture that inspires, empowers, and energizes employees.

To inspire, you must both create resonance and move people with a compelling vision.  You must embody what you ask of others, and be able to articulate a shared vision in a way that inspires others to act.  You must offer a sense of common purpose beyond the day-to-day tasks, making work exciting with fun.

Inspirational leaders have an important role to play in their organization as defined below: 

1.  Provide an inspiring vision and strategic alignment, launch a crusade

2.  Help people connect their personal goals to business goals

3.  Make relentless innovation a religion

4.  Encourage entrepreneurial creativity and experimentation

5.  Involve everyone, empower and trust employees

6.  Coach and train your people to greatness

7.  Build teams and promote teamwork, leverage diversity

8.  Motivate, inspire and energize people, recognize achievements

9.  Encourage risk taking

10. Make work fun

The ability to inspire and motivate workers to high performance is one behavior that separates top-performing leaders from the rest of the pack.